Typically, a solid oxide fuel cell (SOFC) employs an electrolyte of ion-conductive solid oxide such as stabilized zirconia. The electrolyte is interposed between an anode and a cathode to form an electrolyte electrode assembly. The electrolyte electrode assembly is interposed between separators (bipolar plates). In use, generally, predetermined numbers of the electrolyte electrode assemblies and the separators are stacked together to form a fuel cell stack.
As a fuel gas supplied to the fuel cell, normally, a hydrogen gas generated from a raw fuel of hydrocarbon by a reformer is used. In the reformer, in general, the raw fuel of hydrocarbon such as a fossil fuel, e.g., methane, LNG or the like is reformed to produce a reformed raw material gas. The reformed raw material gas undergoes steam reforming, partial oxidation reforming, autothermal reforming, or the like to produce a reformed gas (fuel gas).
In a known fuel cell system (fuel cell apparatus), a single unit case contains a fuel cell, a reformer, a power conversion apparatus for converting direct current power generated in the fuel cell into power in accordance with power supply output specification, a control apparatus, and auxiliary devices.
For example, a fuel cell apparatus disclosed in Japanese Laid-Open Patent Publication No. 2006-140164 has a package 1 as shown in FIG. 12. A purification apparatus 2, an ion-exchanger apparatus 3, and a desulfurization apparatus 4 are provided on a front panel 5 as an outer panel of the package 1.
In the structure, the parts which require maintenance operation are not provided inside the package 1, but near the front panel 5 making up the outer panel of the fuel cell apparatus per se. According to the disclosure, it is possible to easily carry out maintenance operation for parts needed to be replaced or restored for continuing operation of the fuel cell apparatus.
However, in the conventional technique, operating temperatures and functions of the respective components or devices are not considered in the layout. Therefore, in particular, in the case where a high temperature fuel cell (solid oxide fuel cell, molten carbonate fuel cell or the like), or a medium temperature fuel cell (phosphoric acid fuel cell, hydrogen purification fuel cell or the like) is used, the components that should be operated at a low temperature tend to be affected by diffusion of heat or fluid from the fuel cell.